Motor vehicle collision warning systems are becoming more and more common in today's vehicles. These systems are usually arranged to monitor the surroundings of a hosting vehicle and alert a driver thereof of potentially dangerous traffic situations. In order to provide a collision warning a sufficient time ahead of a detected potentially dangerous traffic situation these systems usually rely on a pre-set driver reaction time, i.e. a pre-set time during which an average alert driver would be able to react to an upcoming threat. Thus, a warning is issued this pre-set time ahead of e.g. a predicted collision impact.
However, a driver of a vehicle may from time to time become distracted and thus unfocused. This may be due to a number of different reasons. One such reason may be that the driver is out of an appropriate driving position. The reason here fore may be that the driver is picking something, e.g. sunglasses, from a glove compartment, from the floor or from door pockets etc. The driver may also be attempting to check on or reach something placed in a rear seat or similar. Other reasons include the driver monitoring or caring for an infant or child placed in a child seat somewhere in the vehicle. Thus, all of the above reasons may cause a driver to stop putting full attention to monitoring the road and traffic situation ahead.
Such inattentiveness may, as a fairly secure traffic situation can worsen quite rapidly, cause a driver to be caught off-guard when a warning is issued. Consequently a situation which could have been handled quite comfortably by an average alert driver may turn into a potentially challenging situation for the distracted driver.
A previous attempt at including a state of mind of a vehicle occupant in a motor vehicle collision detection, warning, and countermeasure system is illustrated by document US 2006271258 A1. A controller therein performs a safety countermeasure in response to a determined state of mind of the vehicle occupant. A voice sensor is used to detect voice signals from the vehicle occupant. An occupant classifier is used to determine a state of mind of the vehicle occupant based on the voice signals, and a controller is arranged to perform the safety countermeasure in response to the determined state of mind. The safety countermeasure comprises transmitting the determined state of mind to at least one target vehicle.